PHOTOVOLTAIC SUMMIT 2008: DR. PV, MR. PV AND THE TERAWATT DILEMMA

Dr. PV and Mr. PV met with the Solaroids in San Diego June 18 at IntertechPira’s Photovoltaics Summit 2008 (June 18-20).

Dr. PV is solar energy pioneer and legend Lawrence Kazmerski (Director, National Center for Photovoltaics, National Renewable Energy Laboratory-NREL). He kicked the meeting off by describing what he called The Terawatt Dilemma. The world consumes nearly 15 terawatts of energy now and is expected to be consuming 30 terawatts by mid-century. With oil peaking and global climate change demanding reductions in greenhouse gas emissions and the fuels that generate them, nobody in the New Energy world is more excited about rising energy demand than the Solaroids, the most highly motivated of the solar energy industry.

“We have an energy problem. It’s not a renewable energy problem, it’s an energy problem,” Kazmerski told them.

Details of the Terawatt Dilemma from Cal Tech Professor Nate Lewis. (click to enlarge)

Kazmerski and the Solaroids believe theirs is the solution. Kazmerski’s presentation was a wide-ranging assessment of the current state of the solar energy industry, an examination of how much of those new 15 terawatts the industry has the ability to provide. He didn’t offer conclusive numbers but he was unequivocal about solar energy’s role. “Solar is real…now and for our future.”

Beginning with a summary of the way China’s economic emergence is driving demand, he turned to a review of the 3 big steps in the solar industry’s emergence as a force to meet the demand: Japan’s decision to subsidize solar installations (1994), Germany’s implementation of feed-in tariffs (2000) and the widespread development of “MMP: Methods of Mass Production” that has been driven by the Japanese and German policies and worldwide entrepreneurial innovation.

The U.S. industry’s emergence, with inadequate and inconsistent federal policies stutteringly spurring it, has lagged far behind world leaders until recently but Kazmerski was enthusiastic about state incentive programs such as the California Solar Initiative. He admiringly characterized the Bush administration’s Solar America Initiative, with its goal of driving research and development through public-private partnerships to make solar PV sources in residential, commercial and utility-scale markets cost competitive by 2015, as like “…Nixon going to China.”

Details of the Terawatt Dilemma from Cal Tech Professor Nate Lewis. (click to enlarge)

With his unmatched long-term perspective on solar energy that stretches back to the 1950s, Kazmerski confidently said investment is now bringing the cost of the solar module down and showed a pattern of cell efficiency improvements he called “…the Moore’s Law for PV cells.”

Kazmerski broke the solar industry down into three segments, (1) standard silicon-based photovoltaic cells, (2) thin films and newer materials and (3) concentrating solar technologies. Though big utility money is going into concentrating technologies and thin film efficiencies are impressive, “There is still a lot of life left in silicon,” he said. “Every time another technology does something, silicon surprises us. And accelerates other technologies, like thin film.”

Details of the Terawatt Dilemma from Cal Tech Professor Nate Lewis. (click to enlarge)

That said, Kazmerski offered a comprehensive look at thin films, from silicon-based mono-crystalline and polycrystalline dual gap and triple junction materials to impressively efficient Cadmium Telluride (CdTe) and Copper Indium Gallium diSelenide (CIGS) materials.

He raised some interesting questions about these new materials, echoing other leading scientists who have worried about the relative non-abundance of things like indium (new supplies seem to be emerging) and the potential toxicity of cadmium (it seems to be handled). Kazmerski was enthusiastic about new levels of thin film efficiency (16.5% for CdTe), new levels of mass production capacity (First Solar will be making 1 GW of CdTe by 2009) and new fast printing ("inking") techniques.

Kazmerski only briefly discussed solar power plant technology but, again, affirmed its viability and capacity to contribute to new electricity generation. He did mention, interestingly, that though big solar power installations are usually associated with utility-scale development, he sees them appealing to large commercial operations as well.

There is a category of solar technologies Kazmerski called “disruptive” because they have the potential to be solar industry game changers, to “provide a way of jumping off that learning curve.”

Disruptive technologies include the use of organic materials and biomimetic inorganics as well as concentrator cells. Concentrator cells are “very very expensive very very high efficiency cells” such as those used in communication satellites. They use lenses to focus dense amounts of light on a small amount of photovoltaic material. This shifts the cost of the cell from solar materials to optical materials.

Another type of disruptive technology Kazmerski described is lattice-matched multijunction cells. They use familiar material formulations, such as silicon, but more precisely arrange the junctions between contacts to increase efficiencies.

Kazmerski concluded his remarks with two observations from opposite ends of the realm of practicality. He talked about quantum dot photoluminescence, a highly theoretical field of almost pure research now dominated by Martin A. Green. Quantum dot technology operates on silicon and other materials at spectacularly, infinitesimally small scales to potentially boost productivity hugely. Kazmerski then moved to the opposite end of reality and described the utterly practical importance of improving production plant efficiency.

From Prof. Martin Green (click to enlarge)

Mr. PV, solar energy consultant John Thorton (former Principal Engineer, National Center for Photovoltaics, NREL), began his summary of the state of the solar industry with a simple question: “What’s the value of electricity – when you don’t have any?”

Thornton’s point was that while many discussions about solar installations focus on cost, the unique quality of solar cells is that they can be easily placed where there is no other source of electricity. For such applications price is not the point.

The most high-value applications of solar today, Thornton pointed out, are to keep remote telecommunications systems and remote industrial operating systems going in the absence of grid power. He also described more familiar uses for solar systems in rural, suburban and urban areas.

Thornton ran through the categories of solar materials Dr. PV had covered before him, mentioning the main types of photovoltaic materials (flat plate silicon, thin film silicon, CdTe and CIGS). Instead of going into the details of these materials, he turned to a description of what is important for consumers to know about the information on any solar panel label.

From Prof. Martin Green (click to enlarge)

He pointed out, for instance, that the label's maximum power rating could be affected upward or downward as much as 10% by the ambient temperature (0.5%/degree C) and angle of the sun.

In passing, he noted that the solar panels of a concentrating photovoltaic solar system do not necessarily capture more energy but generate 30% more electricity by tilting to track and keep the sun at its angle of maximum effect.

Much of Thornton’s presentation was about the other elements in a photovoltaic system, the architecture (configuration, placement, orientation, tilt) as well as the inverter that converts the panel-generated electricity from DC to AC. He also described battery storage consideration. He recommended PVWatts – A Performance Calculator as a reference for those interested in evaluating a home’s or building’s system requirements.

Thornton next discussed the importance of the relationship between the solar system and the utility and described the concept of net metering, the idea of a system-owner generating unused electricity, returning it to the utility and winding his/her meter backwards. Without passing judgment, he mentioned the controversial concept of feed-in tariffs, a form of subsidy now used in Germany and Spain with mixed results in which system owners profit from the solar-generated electricity they send to the grid.

This led to Thornton’s observations about the coming challenges of building new and smart transmission. He commented on the synergism between wind and solar energies and on the urgent need to develop efficiencies. He went from there into a discussion of permits, inspections, zoning, interconnect & utility charges and property and sales taxes that might affect solar systems and system owners.

As he closed, Mr. PV came back to where Dr. PV started, at “The Terawatt Dilemma” and how much of the needed 15 terawatts could come from solar. “The primary barriers are cost, manufacturing capacity and material supply.”

Conclusion from NewEnergyNews: A typical house system has 2 to 4 kilowatts. Let’s call it 2.5 kilowatts. 40 houses make 100 kilowatts. 400 houses make 1000 kilowatts, or 1 megawatt. 1000 megawatts (400,000 houses) makes a gigawatt. 1000 gigawatts (400 million houses) is a terawatt.

There were 3.8 gigawatts of solar photovoltaics in 2007. That’s 15 billion 200 million houses. The world needs about 4 times that much emissions-free energy. Is the solar energy industry likely to grow? Do the math.

Postscript: Thornton turned a session-ending question of how long a solar PV system takes to pay itself off over to Summit keynote speaker Paul Maycock, President of PV Energy Systems and Editor Emeritus of PV News. Maycock’s answer: “The question is, is your monthly saving equal to your monthly bill? The answer is yes, right away.

IntertchPira Photovoltaics Summit 2008
June 18, 2008 (NewEnergyNews)

WHO
IntertechPira; Dr. PV, Lawrence Kazmerski (Director, National Center for Photovoltaics, National Renewable Energy Laboratory-NREL); Mr. PV, solar energy consultant John Thorton (former Principal Engineer, National Center for Photovoltaics, NREL)

WHAT
Pre-conference workshops, Intertech Pira Photovoltaics Summit 2008: "The Photovoltaics Revolution – At the Tipping Point…" (Kazmerski, Dr. PV) and "An Introduction to Photovoltaic Systems and Applications" (Thornton, Mr. PV)

The competing solar energy generating materials and their best achieved efficiencies. (click to enlarge)

WHEN
Pre-conference workshops: Wednesday, June 18, 2008; Summit: Thursday/Friday, June 19-20, 2008

WHERE
Hilton San Diego Resort, San Diego, CA

From Prof. Martin Green (click to enlarge)

WHY
The solar energy industry has wide consumer appeal and is rapidly reaching maturity. Coming right after the release of a recent study by Clean Edge indicating solar energy is capable of providing 10% of U.S. electricity by 2025, it was a great time to take a close look at the industry’s pending policy issues, supply chain and manufacturing infrastructure, the state of the technology and the many questions about cost.

From Prof. Martin Green (click to enlarge)

QUOTES
- Kazmerski: “Solar is real – in the future and now…Science and technology funding is dreadfully inadequate…”
- Kazmerski, quoting former President Harry Truman: “The only thing about the future that you couldn’t predict…was the history you didn’t know.”
- Kazmerski: “It is easier to grasp the future if you know what it should look like.”
- Thornton: “Photovoltaics, PVs or solar electricity – it’s all the same.”
- Thornton, quoting Richard Perez of Homepower Magazine: “Every watt not used is a watt that doesn’t have to be produced, processed, or stored.”
- Thornton, on meeting the Terawatt Challenge: “The primary barriers are cost, manufacturing capacity and material supply.”
- Nate Lewis, George L. Argyros Professor of Chemistry, California Institute of Technology: "Without massive quantities (10 - 20 TW by 2050) of clean energy, CO2 levels will continue to rise...The only sufficient supply-side cards we have are "clean" coal, nuclear fission (with a closed fuel cycle), and/or cheap solar fuel...We need to pursue globally scalable systems that can efficiently and cost-effectively capture, convert and store sunlight in the form of chemical fuels..."